Efficiency in 14C photosynthesis and translocation in photosensitive rice varieties

The variation in photosynthetic efficiency per unit leaf area(PE) under different levels of light and nitrogen rates was studied in 10 photosensitive tall and some semi-dwarf rice varieties. Among the cultivars, NC. 1281, a tall indica, consistently showed high PE under water-logged soil. Low light (30 percent normal) and high nitrogen application (80 kg/ha) in some varieties significantly reduced PE. Translocation of 14C assimilates to the ear was more in semi-dwarf than in tall types. (author)